sharp



(No Model.) .2 Sheets--Sh'eet 1.

T. B. SHARP.

MANUFAGTURE OF TUBING..

' Np. 307,993. I Patented Nov. 11.1884.

F l a l l\ \Q \\\\\\Z\\\\\\\\\\\\\\\\\\\\\\\\\\\ Witnesses. Inventor.

[airma l (No Model.)

2 Sheets--Sh eet 2.

T.B.SHARP MANUFACTURE OF TUBING.

Patented Nov. 11,1884.

F l o 5.

V r F' 0-6.

I Wfinesses. Inventor.

THOMAS BUDVORTH SHARP, OF FRENCH VALLS, SMETHWIOK, COUNTY OF STAFFORD, ENGLAND.

MANUFACTURE OF TUBING.

SPECIFICATION forming part of Letters Patent N0. 307,993, dated November 11, 1884:.

Application filed May 26, 1884.

To aZZ whom it may concern:

Be it known that I, Trrorms BUDwoRTH- SHARP,a subject of the Queen of Great Britain, residing at French \Valls, Smethwick, in the county of Stafford, England, have invented certain new and useful improvements in the manufacture of copper and other metallic tubes, and in apparatus employed in the said manufacture, (for which I have received Letters Patent in Great Britain, No. 491, dated January 30, 1883, and in France, N 0. 156,555, dated July 16, 1883,) of which the following is a specification.

In the ordinary method of manufacturing copper and other metallic tubes, a thick hollow cylinder is reduced in diameter and elongated by a succession of drawing-through dies, or a draw-plate having a series of taper or conical holes progressively decreasing in diameter. The exteriorof the tube is reduced in diameter by the die or draw-plate,while the interior of the tube is supported by a cylindrical or nearly cylindrical mandrel,which travels with the tube, or the interior of the tube is supported at the point where the drawing takes place by a bulb on the end of a long rod, the said bulb being fixed by means of the said rod in the eye of the die or draw-plate.

In manufacturing copper and other metallic tubes according to my invention, Idispense with the cylindrical mandrel and bulbed rod referred to, and I employ intheir place a detached or loose plug, preferably of the kind hereinafter described. The fore part of this plug is of the diameter which it is intended the interior of the tube shall have after the drawing process, while the rear part of the said plug is of larger diameter, preferably of a diameter not less than that it is intended the exterior of the tube shall have after the drawingprocess-that is, of a diameter not less than that of the narrowest end of the hole in the die or draw-plate. The fore end of the tube to be drawn down is reduced in the ordinary way,so that it will pass through the drawinghole. The plug is then introduced into the tube, its smaller end foremost. The plug having been pushed up to the draw-plate,the tube is drawn in the ordinary way through the (No model.) Patented in England January 30, 1883,No.49l,- in France July 16, 1883, No. 156,555.

drawing-hole. The plug stations itself by the motion of the tube at the eye of thedrawwall of the drawing-hole, the reduction of the external and internal diameters of the tube as well as the, reduction of the thickness of the metal of the tube takes place. The self-fixing plugwhich I prefer to use consists of a short cylinder of hardened steel, the fore end of which'is of less diameter than the rear part, the junction of the two parts having aconvex shoulder, upon which shoulder the drawing mainly takes place. The plug may, however, be varied in-shape within considerable limits. A spherical or nearly spherical plug, or a conical plug, may be used with nearly the same effect as the plug described, provided the proper relation between the size of the acting parts of the sphere or cone and the acting part of the hole in the draw-plate or die 'be preserved. I prefer to make the holes in the drawplate or die of a trumpet shape, but

holes of the ordinary shape maybe employed.

I will now proceed to describe with reference to the accompanying drawings the manner in which my invention is to be performed.

Figure 1 represents partly in longitudinal section and partly in elevation the apparatus I employ in carrying into effect my improvements in the manufacture of copper and other metallic tubes, the said apparatus being represented in conjunction with a metallic tube in course of manufacture. draw-plate, which may be of the ordinary kind. In place of the fixed bulbed rod or cylindrical mandrel ordinarily employed, I use a detached or loose plug, Z) I)". The fore part, 12 of the plug I) b has the diameter which it is intended the interior of the tube a a shall have after the drawing process. part, b, of the plug 2) b is of larger diameter a is the die or The rear than the fore part, b the rear part, I), being preferably of a diameter not less than that of the exterior of the tube c after drawingthat is, of a diameter not less than that of the narrowest part of the hole in the die or drawplate a. The fore end of the tube whose diameter and thickness of metal is to be reduced is drawn down or contracted in the ordinary way, so that it will pass through the hole in the die or draw-plate a. The plug 1) b is then introduced into the tube and pushed up to the contracted end of the tube, the smaller part b of the plug occupying the said contracted end of the tube, and the shoulder at the junction of the two parts I) b of the plug sea-ting itself upon the shoulder formed by the contraction of the tube. The contracted end of the tube being passed through the hole in the drawplate a, the tube is drawn by the ordinary appliances through the hole in the draw-plate. By the motion of the tube a c the plug b 11 stations itself at the eye of the die or drawplate a-that is, at the place where the drawing is effected, the diameter of the tube and the thickness of the metal being reduced between the shoulder at the junction of the parts I) b of the plug and the entrance to and narrow part of the hole in the said die or-drawplate a: The plug 1) 1) becomes self-fixed and retains its position during the drawing of the whole length of the tube. In some cases it is desirable to expand the tube being operated uponbefore contracting it. This method of operating is illustrated in longitudinal section in Fig.- 2, where a is the die or draw-plate and b b b is the self-fixing plug. In this case the plug is a cylinder, 1), having conical ends b b, andthe manner in which thetube c c c is op-' erated upon by the shoulder of the conical end I) and-the hole in the die or draw-plate a will be understood from the description hereinbefore given with reference to Fig. 1. As the tube, Fig.- 2, is drawn through the die or drawplate a, that part of it in which the cylindrical part b of the plug 1) I)" b is situatedis increased in diameter, as at 0 Fig. 2, before it is reduced to the diameter and thickness shown at c ,Fi g. 2. In order'to introduce the plug 1) b 1) into the tube to be operated upon, the fore end of the tube is slit or divided longitudinally, preferably, at three places, as represented at d in cross-section in Fig. 3, and side elevation in Fig. 4. By this slitting of the tube the plug b b b can be introduced, the three parts into which the end of I the tube has been divided separating asthe plug is forced into the split tube; Theplug b b 11 having been introduced into the tube a, the split end of the tube isso far contracted as to permit it to pass through the hole in the die or draw-plate a. The drawbar e is then inserted in that part of the tube which has been passed through the draw-plate, and the extreme end 0 of the tube is next contractedby driving the ring or collar f up to the head e of the draw-bar e. of the tube is then conducted in the ordinary way, and progresses in the manner hereinbe fore described, and represented in Fig. 2. By

ployed 'metal at diflerent parts;

The drawing this method of manufacture, different thicknesses of metal may be given to diii'erent parts of the tube under operation. For example, if, as illustrated in Fig. 2, a ring or drawplate, 9, be placed upon the tube 0, having a hole or eye of larger diameter than the part c of the tube, but of less diameter than the part c of the tube, and if the said ring or draw-plate g be forced up to and stationed at the position indicated in dotted lines at 9, Fig. 2, the external diameter of the tube will be diminished as the expanded part 0" passes through the ring or draw-plate at 9 As the final external diameter of the tube is determined by the'sizeof the hole or eye in the die or draw-plate a, the tube after this treatment while having the same external diameter as it would have had if the ring 'or draw-plate had notbeen employed, the thickness of the metal in the tube produced is less than it would have been if drawn without the'said ring or draw-plate 9. Thus by the methodof manufacture described a tube may "be produced having throughout its whole'length the same external diameter, but having at any de sired parts "a greater or less internal diameter, according as the drawing is efi'eeted, with or without the draw-plateg, the internal dia1iieter being greatest when the draw-plate g "is used, and least when the drawing is efl'ected without the'said draw-plate g. Fig. 5 represents in longitudinal section a tube ofthis kind, the ends having a' g'r'eater thickness of metal, or of less internal diameter, than the other portion of the tube. Tubes of thiskind' areuseful for locomotive and other boilers, and for all purposes where greater strength isrequired in one part of the tube than in another. From the description given it will be understood that the additional thickness of metal or diminished internal diameter mayb'e given to any part of the tube. Fig. 6 represents in lon i: tudinal section a modification of 'themanufacture and apparatus represented in Fig. 2.

In this modification the plug hhhas a nearly spherical head, h, the portion h being cy'lindrical. The action of themodificatio'n, Fig. 6, is essentially the same as that'described with reference' to' Figs. 2 and 4, and may be emfor similar purposethat is, for'protubes having difi'erent thicknesses of I wish it, however, to be understood that the method of manufacture described with reference to Figs. 2, 4, and

ducing 6 may beemployed with advantage to pro" duce tubes having the same internal and ex ternal diameter throughout, the expansion of the tube before'its contraction disclosing any defect in the tube being operated upon," and the issue of defective tubes into commerce is thusavoided.

The plug 1) II b, Fig. 2, may have a cylindrical termination at the end entering the draw-plate similar to the end I) of the plug b b Fig. 1. In-all cases where the plug has a cylindrical termination the'i'nterior of the tube operated upon is planished or made smooth by the said cylindrical termination, excepting in those cases in which the ring g is employed. In such cases there is no planishing of the interior of the tube. 7

Having now described the nature of my invention, and the manner in which the sameis to be performed, I wish it to be understood that I claim as my invention-- 1. The combination, with a die or drawplate, of a loose self-adjusting core having a varying diameter, and adapted to be located within a tube to be drawn, the greater diameter of the core being larger than the diameter of the entrance to the eye of the plate through which the tube is to be drawn, substantially as described.

2. The within-described method of drawing tubes, consisting in expanding the tube beyond its original external diameter previous to passing it through the draw-plate, and then by said plate contracting its diameter below its original external diameter, substantially as described. Y

3. The within-described method of drawing tubes and forming them with avarying inter- 25 nal diameter, consisting in expanding the internal and external diameter of the tube and then reducing the external diameter of the expanded portion without altering its inner diameter, and afterward contracting the diameo ter of the tube, substantially as set forth whereby the tube is formed with auniform external and varying internal diameter.

4. The combination of a multiple of drawplates or dies, the eye of one being of agreater 5 diameter than the eye of the other, and a loose self-adjusting core having avarying diameter, and adapted to be located within a tube to be drawn, the greater diameter of the core being larger than the diameter of the eye of the final o draw-plate that is to reduce the diameter of the tube, substantially as described.

THOMAS BUDWORTH SHARP. [L 8.] \Vitnesses:

GEORGE SHAW, RICHARD SKERRETT. 

